Sterilization and preservation of fruit juices



p 35 amounts of the fruit juice Patented Aug. 27, 1929.

UNITED STA Es PA NT- LEMMIE BOSCOE CLEVELAND,

ACADEMY OF SCIENCES,

srnnmrzazrron Ann :rnnsnnva'rron or Faun; anions.

No Drawing.

(This invention relates to the and preservation of fruit juices, a new and improved method of sterilization and preservation, as well as the sterilized and preserved fruit juices resulting therefrom..

, According to the present invention, the fruit juices, after beingclarified and freed from pulp, are subjected to the action of oxygen under pressure for a suflicient -time-to bring about their sterilization and preservation. The fruit juices maybe separated from the pulp in an suitable'manner and then ,freed from pulp y suitable treatment, as by filtration through a suitable filter, or by centrifugal treatment in apparatus similar to a cream separator. By removin the pulp from the fruit juice, a clear liqui is obtained and one in which there will be no precipitate after sterilization sterilization. Moreover, the freer the juice is of pulp, the less apt it is to undergo change when confined in oxygen under pressure in accordance with the process of the present invention, for the oxygen seems to act a great deal more on the pulp than on the clear liquid.

This is particularly true in plums andapples.

The clear liquid is next placed in containers in which it is to be sterilized. Where the sterilized fruit juice is to be marketed. in bottles or other suitable containers, it may be laced in these containers before sterilization and subjected tosteri ization while contained therein. It is evident that containers of various sizes can be used, and that, where large are to be sterilized,-

barrels or other large size containers can be used, and the fruit juice subjected to the sterilizing treatment while contained therein. The containers in which the fruit juice is 40 placed during sterilization should, i stoppered, have stoppers which will allow the free passage of gas into the container and of gas out therefrom, while not allowing microorganisms to enter the container; or the container should otherwise be protected from re infection after it has been sterilized, as by sealing the container with a sterile stopper or closure while the contents are in a sterile condition. -Whatever the form or size or arrangement or construction of the container or containers in which the fruit juice is placed, they are treated in the container with oxygen under pressure. In the case of large containers, 56 oxygen under pressure may be forced into the and includes is not necessary to bring about sterilization,

Application filed December '21, 1925, serial m. 76,508.

container in sufiicient amount and under a 'snificiegg pressure to bring about the sterilization. ith smaller containers, they may in turn be enclosed-in a large container into which the oxygen under pressure is intro duced. Special steel tanks may be-used-for this purpose, whichare gas tight and which will hold'the oxygen under pressure while the fruit juice in the containers therein :is being'subjected to the oxygen under pressure and is undergoing sterilization. The time of treatment of the fruit juice with theoxygen will vary, dependin upon the I pressure of the oxygen, the kind 0 fruit nice, the temperature at which the juice is kept, 7 etc.- .In general, the time will be anywhere ,frdni ten-to twelve hours upto two or three days or evenmore. The pressure of oxygen Y may advantageously be that readily obtainable with commercial oxygen supplied in cylinders, although the full pressure of the oxygen in the cylinder is' not required. Ingeneral, commercial oxygen with a.high.partial pressure of oxygen hould be used. Most commercial oxygen has at least 97% oxygen and some. of it approaches 99 or 100%,.

Most fruit juices, when kept for five days at 100 atmospheres of. commercial oxygen pressure, are sterilized. Ina few cases, however, a period of boutsix .days has been required. If higher pressures-are used, the time becomesshorter; while if lower pressures are used, it becomes somewhat longer; The fruit juice can be maintained under pressure for long periods ofitime, but in general this 'a maximum of about six days being ordinarily Where complete sterilization is not neces-- sary or required, oxygenat a lower pressure or for a shorter time can be used; Oxygen at a much lower pressure than that indicated will completely inhibit the growth of bacteriawithout killin them. The multiplication o practically allliacteria is completely inhibited even with oxygen pressure as low as atmospheric, if the treatment is continued for asufiicient time. 'However, there are usually enough enzymes, which are not destroyed at low pressures to bring about a slight alcoholic fermentation. In some instances, this-slight alcoholic fermentation, with the development of a small percentage of alcohol, ma be unobjectionable, or may even be desira le; but

where such changes are'to be avoided, and

sterilization is to be eflected, higher oxygen The-fruit juices which are and do p should be used.

Investigations have shown that while some bacteria are outright-in less than five 8 days time at a pressure of 100iatmospheros of oxygen, and while' many are killed in five time, a few are-not killed even in ten days time, or may not be killed during this period of time. Invmations havepho'wl9 ever, shown that these bacteria, even though they are not killed by the high oxygen pres sure, do not develop, that is multiply, in the fruit'juics. In fact, the fruitjuice medium is so unfavorable an environment forthem that they usually all die within a period of about two to three weeks, and in this way complete sterilization is eventually realized as a result of the fruitjuices in oxygen under pressure, that is. by oxygenation. It maybementioned that harmful or pathogenic bacteriaaretheeasiestomstokillwith oxygen according to the process of the present invention.

After the fruit juices have been subjected to the gen under pressure for a suflicientpuiod (igtime, the oxygen pressure can be released and theoxygen transferred to 'another container and. stored for'further' use. The containers may however be sealed while they still contain oxygen under pressureso that the fruit juice will be held in a container in which the atmosphere is oxygen under pressure; or the containers may be sealed while they contain oxygen under pressure ap- P tles, the bottles may be capped while they are dill in an oxygen atmosphere with sterile caps so that the contents of the containers.

are protected from reinfection. The preserved and sterilized fruit juice in bottles or other containers, thus hermetically sealed, may then be labeled and stored for subsequent shipment or use.

Vhen .fruit juices are sterilized or pre served by confining them in oxygen under pressure, most of their natural color islost, and in most juices there is a slight change in taste, owing to a very slight increase in acidity, but ordinarily be unobjectionable, and may even be desirable. In general, however, no change in taste occurs, or at least only a very slight change, in the juiw of grape fruit and lemons.

Sugar in any quantity dwired may be added to. the juices before they are confined in oxygen under pressure. Moreover, the fruit jmces may be concentrated, and preserved in concentrated form, either with or without the addition of sugar.

atmospheric. In the case of hotprwerved according to. the present invention can be-kept for long periods of time while retaining their natural fruit flavor, or with only a slight increase in acidity. In particular, they are free from any cooked taste such as results from sterilization or pasteurization by heating, and they are also free from chemical preservatives.

It will thus be seen that the present inven- 4 tion provides a new and improved method for the sterilization-and preservationuof fruit juices in which the knitjuices are subjected to the action of oxygen under pressure for a suflicient period of time to bring about sterilization, and that the fruit juices are then kept in suitable containers where the sterilized condition is maintained- The invention also presents a new and improved form of fruit juices in whieh the fiuit juices are preserved in an oxygenated conditron.

I claim: 1. The method of preserving fruit juices which comprises v the juice and subthe juice and sub- 7 to effect substantially complete sterilization thereof. 4

3. The method of preserving fruit juices which comprises clarifying the juice and subjecting the fruit juices to an oxygen pressure of about atanospheros fora sufiicient period of time to efiect substantially complete sterilization thereof.

4. The method of preserving fruit juices which comprises thejuice and subecting the same to-the action of oxygen under pressure for a sufiicient time to effect the desired sterilization, and sealing the fruit juics in an oxygen atmosphere.

'5. The -method of p fruit juices which -comprises clarifying 5 9 Ju ce and subjecting the fruit juices to the action of oxygen under pressure of about 100 atmospheres, and

sealing the preserved fruit juices in atmosphere of oxygen.

6. As a new prodnct, a composition com- I prising a sterile clarified fruit juice and oxygen under mm and. relatively substantially free other gaseous materials.

-In testimony whereof I aflix my 

